This invention relates to an automatic adjuster mechanism for a mechanically actuated disc brake mechanism.
Disc brakes actuated by mechanical mechanisms normally are designed with only a relatively limited application stroke. However, as the friction elements used in the disc brake wear, the actuating stroke tends to increase unless the retraction of the friction element is controlled. For this reason, most disc brakes with mechanical actuators require an automatic adjustment mechanism which is responsive to increased stroke of the actuating piston during brake actuation to thereby adjust the brake so that the retraction of the piston and the corresponding friction elements are limited to a substantially predetermined amount, so that the stroke required of the mechanical actuator does not increase as the friction linings wear.
The present invention discloses an automatic adjuster for a mechanically actuated disc brake which uses many of the same components used in the wedge brake adjuster disclosed in U.S. Pat. No. 3,246,723, which is owned by the assignee of the present invention. However, this adjuster has been redesigned to accommodate the disc brake structure, and has also been changed so that the brake adjustment takes effect on the brake application stroke, but only prior to the time that substantial braking forces have been generated. The adjustment mechanism indexes on the brake release stroke upon movement of the extendible member in excess of a predetermined distance.